Fully-threaded bioabsorbable suture anchor

ABSTRACT

A suture anchor includes a threaded anchor body having a first central bore in communication with a second central bore. The suture anchor includes an internal eyelet formed of a loop disposed at least partially inside the first central bore. The ends extending from the loop are tied together to form at least one knot which is housed in the second central bore provided at the distal end of the anchor body. The knot increases the pullout strength of the suture even in soft bone, provides increased suture fixation, and eliminates the anchor “pull back”.

REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. application Ser. No.11/224,060 filed on Sep. 13, 2005.

FIELD OF THE INVENTION

The present invention relates to an apparatus and method for anchoringsurgical suture to bone. More specifically, the present inventionrelates to arthroscopic apparatus and methods for anchoring suture tobone using a fully-threaded bioabsorbable suture anchor having a loopinserted into the suture anchor.

BACKGROUND OF THE INVENTION

When soft tissue tears away from bone, reattachment becomes necessary.Various devices, including sutures alone, screws, staples, wedges, andplugs have been used in the prior art to secure soft tissue to bone.Recently, various types of threaded suture anchors have been developedfor this purpose. Some threaded suture anchors are designed to beinserted into a pre-drilled hole. Other suture anchors are self-tapping.

Problems can arise if the structure for attaching the suture fails,allowing the suture to become detached from the anchor. Also, the sutureoften is exposed to abrasion or cutting by sharp or rough areas alongthe walls of the bone canal into which the anchor is inserted.

Further, the prior art suture anchors having eyelets extending from theproximal ends require countersinking of the eyelet below the bonesurface to avoid having the patient's tissue abrade against the exposedeyelet. As a result, suture attached to the eyelet is vulnerable toabrasion by the bony rim of the countersunk hole into which the sutureanchor is installed. In addition, in biodegradable prior art devices,the eyelet can degrade rapidly, causing the suture to become detachedfrom the anchor prematurely.

Accordingly, a need exists for a threaded suture anchor to which sutureis secured effectively so as to prevent detachment of the suture andeliminate anchor “pull back.” In addition, a need exists for sutureanchors having eyelets that will not abrade tissue and do not requirecountersinking. Suture anchors having a small core diameter providingmaximum pullout strength even in soft bone and maximum suture fixationstrength are also needed.

SUMMARY OF THE INVENTION

The suture anchor of the present invention overcomes disadvantages ofthe prior art, such as those noted above, by providing a threaded sutureanchor having an eyelet formed of a loop of a flexible strand ofmaterial that is disposed within the suture anchor during themanufacturing process. The suture anchor is preferably formed ofbiodegradable material.

The threaded suture anchor of the present invention has a central body,a distal end, and a proximal end. The body preferably tapers from thenarrow distal end to terminate in a blunt or rounded proximal end. Theproximal end of the suture anchor body preferably has a rectangulardrive socket or bore, that is configured to accept a drive head thatdrives the fully-threaded anchor body.

The internal loop preferably extends through more than half the lengthof the fully-threaded central body and forms an eyelet at the proximalend. The loop is located at least partially within the drive socket.Multiple sutures for tying down tissue may be looped through the loop,allowing the sutures to slide smoothly with minimal friction. In apreferred embodiment of the invention, the ends of the internal loop aretied together to form at least one knot which is housed in a recessedregion provided at the distal end of the anchor body. The knot increasesthe pullout strength of the suture even in soft bone, provides increasedsuture fixation, and eliminates the anchor “pull back.”

Advantageously, the anchor of the present invention may be preassembledin a sterile package with at least another surgical instrument such as adrill or cutting punch for creating a pilot hole before the sutureanchor is inserted, or may be preloaded on a driver that drives theanchor with attached sutures in a pilot hole.

Other features and advantages of the present invention will becomeapparent from the following description of the invention, which refersto the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view of a fully-threaded suture anchoraccording to the present invention, and with two suture strands loopedthrough the internal loop of the fully-threaded suture anchor.

FIG. 2 is a perspective view of the fully-threaded suture anchor of FIG.1, but without the two suture strands looped through the internal loopof the fully-threaded suture anchor shown in FIG. 1.

FIG. 3 is a proximal end view of the fully-threaded suture anchor ofFIG. 2.

FIG. 4 is a cross-sectional view of the fully-threaded suture anchor ofFIG. 2.

FIG. 5 is a distal end view of the fully-threaded suture anchor of FIG.2.

FIG. 6 is another perspective view of the fully-threaded suture anchorof FIG. 2.

FIG. 7(a) is a perspective view of a first exemplary embodiment of acannulated driver preloaded with the fully-threaded suture anchor ofFIGS. 1-6.

FIG. 7(b) is an enlarged view of the fully-threaded suture anchor ofFIG. 7(a).

FIG. 8(a) is a perspective view of a second exemplary embodiment of adriver preloaded with the fully-threaded suture anchor of the presentinvention, and with needles attached to the two suture strands loopedthrough the internal loop of the fully-threaded suture anchor.

FIG. 8(b) is an enlarged view of the needles attached to thefully-threaded suture anchor of FIG. 8(a).

FIG. 9(a) is a perspective view of a third exemplary embodiment of adriver preloaded with the fully-threaded suture anchor of the presentinvention, and with punch needles attached to the two suture strandslooped through the internal loop of the fully-threaded suture anchor.

FIG. 9(b) is an enlarged view of the fully-threaded suture anchor ofFIG. 9(a).

FIG. 10 is a perspective view of the cannulated driver shown in FIG.7(a).

FIG. 11 is another perspective view of the cannulated driver of FIG. 10.

FIG. 12 is a side view of the cannulated driver of FIG. 11.

FIG. 13 is a cross-sectional view of the handle of the cannulated driverof FIG. 10.

FIG. 14 is a side view of the handle of the cannulated driver of FIG.10.

FIG. 15 is a top view of the handle of the cannulated driver of FIG. 10.

FIG. 16 is a top view of the driver shown in FIG. 8(a).

FIG. 17 is a perspective view of the driver shown in FIG. 16.

FIG. 18 is a side view of the shaft and head of the driver shown in FIG.16.

FIG. 19 is a top view of the shaft and head shown in FIG. 18.

FIG. 20 is a top view of the handle of the driver of FIG. 16, with thecover removed.

FIG. 21 is a proximal end view of the handle shown in FIG. 20.

FIG. 22 is a partial cross-sectional side view of the driver of FIG. 20.

FIG. 23 illustrates a schematic view of the fully-threaded suture anchorof FIG. 1, having a recessed loop, and with two suture strands loopedthrough the internal loop of the fully-threaded suture anchor.

FIG. 24 illustrates a top view of the cannulated driver of FIGS. 10-15loaded with the fully-threaded suture anchor of FIG. 23, and with thetwo suture strands threaded through the cannula of the driver.

FIG. 25 illustrates a top view of the cannulated driver of FIGS. 10-15loaded with the fully-threaded suture anchor of FIG. 23, and showing theloading path of the two suture strands threaded through the cannula ofthe driver.

FIG. 26 illustrates a side view of the cannulated driver of FIGS. 10-15loaded with the fully-threaded suture anchor of FIG. 23, and showing thetwo suture strands threaded through the cannula of the driver andsecured to the driver.

FIG. 27 illustrates a side view of the driver shown in FIGS. 16-22before being loaded with the fully-threaded suture anchor having twosuture strands with attached needles.

FIG. 28 illustrates a schematic view of the fully-threaded suture anchorof FIG. 1, having a recessed suture loop and two suture strands loopedthrough the loop of the fully-threaded suture anchor, the two suturestrands having attached needles.

FIG. 29 illustrates a perspective view of the driver of FIG. 27 loadedwith the fully-threaded suture anchor of FIG. 28, and with the twosuture strands with attached needles partially threaded through a sidecannulation of the driver.

FIG. 30 illustrates another perspective view of the driver of FIG. 27loaded with the fully-threaded suture anchor of FIG. 28 and with the twosuture strands and attached needles secured to the driver.

FIG. 31 is a perspective view of a punch employed to create a pilot holefor the fully-threaded suture anchor of the present invention.

FIG. 32 is a distal end view of the punch of FIG. 31.

FIG. 33 is a schematic cross-sectional view of a bone fragmentundergoing a suture anchor installation in accordance with a method ofthe present invention and at an initial stage.

FIG. 34 illustrates the bone fragment of FIG. 33 at a stage of sutureanchor installation subsequent to that shown in FIG. 33.

FIG. 35 illustrates the bone fragment of FIG. 33 at a stage of sutureanchor installation subsequent to that shown in FIG. 34.

FIG. 36 illustrates the bone fragment of FIG. 33 at a stage of sutureanchor installation subsequent to that shown in FIG. 35.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now to the drawings, where like elements are designated bylike reference numerals, FIGS. 1-6 illustrate a fully-threadedbioabsorbable suture anchor 100 of the present invention. Thefully-threaded suture anchor 100 includes a body 4 provided in the shapeof a tapered cylinder and having a distal end 12 and a proximal end 13.

As shown in FIG. 1, the fully-threaded suture anchor 100 is providedwith a continuous thread 6 which wraps around the body 4 in a clockwisedirection, the crest of the threads tapering from wide to narrow fromthe proximal to the distal end of the anchor. The proximal threads ofanchor 100 with the widest crest surfaces are designed to engage thethin cortical shell in osteopenic bone to prevent anchor “pull back,”which could cause the back of the anchor to be proud to the bone. In anexemplary embodiment, suture anchor 100 is provided with about eightthread flights wrapping around body 4, with the angle of the proximalsurface of each thread being approximately between one-third andone-fourth the angle of the distal surface of each thread relative tothe horizontal. For example, in the preferred embodiment, the proximalsurface of each thread has an angle of 12° relative to a planehorizontal to the axis of the suture anchor, while the distal surface ofeach thread has an angle of 45° relative to the same horizontal plane.

By providing the suture anchor 100 with continuous threads running fromthe tip to the proximal end where the driver engages, the threadpotential is maximized and the wasted space is minimized. Thefully-threaded design of the anchor of the present inventionsubstantially improves pull-out strength compared to suture anchors withprotruding eyelets, and prevents anchor “pull-back” that can occur withcountersunk anchors.

As shown in FIGS. 1 and 4, the suture anchor 100 has a cylindricallyshaped bore or socket 10 starting from a rectangularly shaped opening 11at the proximal end and extending into the anchor body 4 approximatelytwo-thirds of the length therethrough. Distally of the bore 10, anchorbody is provided with a knot socket 20 which extends from the distal end12 of the anchor. Knot socket 20 may have various shapes andconfigurations, for example, a cylindrical shape, as shown in FIG. 5.Bore 10 communicates with knot socket 20 through passage 40.

The proximal surface and associated edges of suture anchor 100 definingthe rectangularly shaped opening 11 is rounded and smooth. Preferably,the proximal surface of the suture anchor 100 forming the periphery ofthe opening 11 forms a rounded lip 18 (FIG. 4) so that opening 11 has aslightly wider diameter than the main portion of the cylindrical bore10. With the smooth and rounded proximal end provided in the anchor ofthe present invention, sutures threaded through the bore 10 and opening11 will not be abraded by any sharp edges, and will not become frayedupon pressure or rubbing against the anchor at the proximal opening.

In a preferred embodiment, diameter Ø₂ (FIG. 4) of opening 11 issubstantially equal to that of the knot socket 20, but larger thandiameter Ø₃ of the passage 40 and smaller than outside diameter Ø₁ ofthe anchor body 4. Preferably, the outside diameter Ø₁ of the anchorbody 4 is about 3 to about 8 mm, more preferably of about 5.5 mm, andthe diameter Ø₂ of the opening 11 and socket 20 of about 1.5 to about4.5 mm, more preferably of about 3 mm. In an exemplary embodiment, body4 of suture anchor 100 has a length of about 0.6 in. and an exteriordiameter of about 0.22 in. (5.5 mm) as measured across the outerdiameter of the threading at the proximal end of the anchor.

Referring back to FIG. 1, a flexible strand 30, preferably suture, isthreaded into the anchor body 4, with one end of the suture strand beingthreaded through the socket 20, passage 40 and bore 10 to form a loop oreyelet 32 located at least partially within bore 10 at the proximal end13 of the anchor 100. Ends 31 a, 31 b extending through the anchor fromthe distal end 12 of the suture anchor are tied to form at least oneknot 34.

In the preferred embodiment illustrated in FIG. 1, the loop 32 iscompletely recessed from the proximal end 13 of the anchor body 4.However, the invention also contemplates embodiments according to whichthe loop 32 extends out of the suture anchor 100 by a distance of about0.5 to about 1.5 mm, more preferably of about 1 mm. In alternativeconfigurations, the loop 32 may be also located completely outside ofthe bore 10 of the anchor 100. Thus, although the embodiment of FIG. 1illustrates eyelet 32 disposed completely within the anchor body 4, thisembodiment is only illustrative and the invention is not limited to it.The position and size of the eyelet of the present invention isdetermined according to the characteristics of the arthroscopicprocedure, and the need to precisely orientate the eyelet during anchorinsertion to optimize suture sliding characteristics.

The fully-recessed loop 32 of FIG. 1 has the ability to self-align,eliminating the need to determine eyelet alignment as it applies to theorientation of the tissue edge. The fully-recessed loop 32 also enhancessuture slideability compared to conventional anchors with protrudingeyelets, and allows the suture to slide against the smooth inner edge ofthe anchor reducing the potential for suture abrasion from the corticalbone edge.

At the distal end 12 of anchor 100, flexible strand of material 30 formsat least one knot 34, which is preferably an over-hand knot. Knot 34 ishoused in the knot socket 20 and rests on most distal surfaces 37 ofregions 35 of the anchor body 4 that define the passage 40 having adiameter narrower than that of the sockets 10 and 20. To increase thepull out strength of the strand 30 from the anchor, knot 34 may beoptionally coated with a glue material to increase its strength andfacilitate adherence to the walls of the socket 20. Knot 34 increasesthe pullout strength of the strand even in soft bone, provides increasedfixation, and eliminates the anchor “pull back.”

The strand 30 may be formed of any flexible material. In the preferredembodiment, strand 30 and loop 32 are formed of a high strength suturematerial such as the one described in U.S. Pat. No. 6,716,234 to Graftonet al., the disclosure of which is incorporated by reference in itsentirety. In additional embodiments, the strand 30 may be insert-moldedinto the anchor in the manner described in U.S. Pat. No. 5,964,783 toGrafton et al., the disclosure of which is also incorporated byreference in its entirety.

The anchor body 4 is preferably formed of a translucent or transparentpolymer material, and is preferably made of bioabsorbable materials suchas polyglycolic or polylactic acid polymers. Accordingly, flexiblestrand 30 is visible through the body of the fully-threaded anchor 100to provide visual confirmation of strand encapsulation within theanchor. Advantageously, the flexible strand of material 30 and theanchor body 4 are made of materials selected such that the loop 32 willnot biodegrade before anchor body 4. As used in the present application,the term “bioabsorbable” is considered to be interchangeable with theterm “biodegradable,” “resorbable,” and “absorbable” to mean that thedevice can be absorbed by the body over time. Also, the measurements,angles and ratios between the dimensions of the suture anchor may bevaried from those described above so as to be suitable for theconditions and applications in which the suture anchor is to be used.

Optionally, the suture anchor can be distributed with at least onestrand of suture already threaded through the loop 32. For example, FIG.1 illustrates suture strands 42, 44 attached to the loop allowing thesutures to slide smoothly with minimal friction. In an exemplaryembodiment, the suture strands 42, 44 may be FiberWire composite suturesof alternating colors to maximize repair strength, aid in suturemanagement and provide superior tying characteristics.

FIGS. 7(a), 8(a) and 9(a) illustrate various embodiments of drivers 200,300, 400 used to install the fully-threaded suture anchor 100 of thepresent invention. FIG. 7(a) illustrates cannulated driver 200 preloadedwith the fully-threaded suture anchor of FIGS. 1-6 and with suturestrands 42, 44 attached to the loop 32. As explained in more detailbelow with reference to FIGS. 10-15 and 23-26, suture strands 42, 44 arethreaded through the cannula of the driver 200 and secured on a hook onthe handle of the driver, to allow the distal end of the head of thedriver to be inserted into the opening 11 and bore 10 of the anchor 100so that the suture anchor is driven into a pilot hole.

FIG. 8(a) illustrates a second embodiment of a driver of the presentinvention. Driver 300 (which will be described in more detail in FIGS.16-22) is not cannulated, but rather presented with a slot or sidecannulation 360 in the shaft 330. The slot allows suture strands thatare provided with needles 380 (FIG. 8(b)) and that are attached to theloop 32 of the anchor 100 to pass through the slot and around the sidesof handle 310, to be further secured in needle slot 388 of the handle.

FIG. 9(a) illustrates yet another embodiment of a driver of the presentinvention, according to which driver 400 is employed in connection withsuture strands with punch needles 440 (FIG. 9(b)) that are attached tothe loop 32 of the anchor 100 of the present invention.

FIGS. 10-15 illustrate details of the first exemplary embodiment ofdriver 200 used to install the fully-threaded suture anchor 100 of thepresent invention during an arthroscopic procedure. The driver 200 isprovided with a head 250, a shaft 230 and a handle assembly 210. Thehead 250 of the driver is configured to be received within anchor socket10 of the fully-threaded suture anchor 100 of FIGS. 1-6. In an exemplaryembodiment, the drive head is rectangularly shaped and has a width and alength which substantially corresponds to the width and length ofopening 11 in suture anchor 100. Preferably, the drive head is slightlyshorter and has a slightly smaller width than opening 11, so that thefit is not too tight, yet ensures secure engagement for driving thesuture anchor into bone.

The shaft 230 preferably comprises an elongate, narrow diameter bodysuitable for use in remote procedures performed through percutaneoustissue punctures, such as arthroscopic, laparoscopic and other invasiveprocedures and the like. The shaft typically has a length of about 5 cmto about 20 cm, preferably about 15 cm. The diameter of the shaftassembly is sufficiently small to facilitate introduction through accesssheaths, cannulas, trocars, and the like, typically being less thanabout 10 mm, preferably about 5 mm.

The handle assembly 210 preferably includes an elongated double hook 252extending substantially along the length thereof and having a hook atthe proximal end and at the distal end thereof, and a clip 260 formed atone end region of the double hook 252. As explained in more detail belowwith reference to FIGS. 23-26, when driver 200 is engaged with sutureanchor 100, excess lengths of suture 42, 44 passed through the proximalend of driver 200 can be wrapped around the double hook 252, and theends of the sutures can be secured in the clip 260. In this manner, thesuture strands 42, 44 can be prevented from becoming tangled orotherwise interfering with the surgeon's work.

Driver 200 is preferably constructed to withstand an application ofabout 20 in/lb of torque. Preferably, although not necessarily, at leastthe shaft and drive head are made of stainless steel. However, othermaterials may be used which provide the necessary strength and rigidityfor installing the suture anchor of the present invention into corticalbone.

The anchor 100 and driver 200 may be provided to the surgeon as apreformed assembly with the sutures 32, 34 pre-threaded through loop 32and through the cannula of the driver and secured on the handle.

FIGS. 16-22 illustrate details of the second exemplary embodiment ofdriver 300 used to install the fully-threaded suture anchor 100 of thepresent invention during an arthroscopic procedure, preferably during anopen procedure such as mini-open rotator cuff repairs. The driver 300 isdifferent from the driver 200 described above in that driver 300 allowsinstallation of a fully-threaded suture anchor that has attached atleast one strand of suture with a surgical needle. Thus, driver 300 isnot cannulated but rather comprises a slot or side cannulation 360provided for about half the length of the shaft 330 and defined by breakedges 350. The side cannulation allows suture strands 342, 344 (FIG.8(b)), which are received in the cannulation, to be provided withsurgical needles 380 (FIG. 8(b)) at one end, which would not be possibleif the driver had a central (fully closed) cannulation.

When driver 300 is engaged with suture anchor 100, excess lengths ofsuture 342, 344 with attached needles 380 can be secured in recessregion or cavity 388 (FIG. 8(b)) of the handle 310. The cavity 388 isaccessed by opening a pivotable hatch 399. In this manner, the needles380 and suture strands 342, 344 are wrapped around tie-down barsdisposed in the inside of the housing cavity when the path is closed.Thus, surgical needles 380 may be safely stored within the handle 310,preventing therefore any piercing of surgical gloves and any problems inmaintaining the needles sterile.

FIGS. 20-23 illustrate details of the housing cavity 388 provided in thehandle 310 of the driver 300. As shown in FIG. 20, cavity 388 isprovided with a plurality of slots 396 and tie-down bars 393, that allowthe surgical needles 380 to be “parked” or secured within the slots andthe bars. If desired, a plurality of sutures with or without needles maybe housed within the housing cavity 388. The cavity 388 is accessed byopening the pivotable hatch 399. Driver 300 is also configured to bereceived within anchor opening 11 of the fully-threaded suture anchor100 of FIGS. 1-6.

FIGS. 23-26 illustrate the cannulated driver of FIGS. 10-15 loaded withthe fully-threaded suture anchor of FIG. 23. As shown in FIG. 24, thetwo suture strands 42, 44 are first threaded through the cannula of thedriver 200, and the distal end of the drive head 250 (FIG. 24) of thedriver is then inserted into the opening 11 of the anchor 100. Thesutures exiting the proximal end of driver 200 are wrapped around thedouble hook 252 and/or clipped in clip 260.

FIGS. 27-30 illustrate the driver 300 of FIGS. 16-22 loaded with thefully-threaded suture anchor 100 and provided with two suture strands342, 344 having attached surgical needles 380. As shown in FIG. 29, thetwo suture strands 342, 344 are first passed through side cannulation360 of the shaft of the driver 300, so that the distal end of the drivehead 350 of the driver is then inserted into the opening 11 of theanchor 100. The sutures passed through the side cannulation are pulledtoward the proximal end of the driver 300 and the suture strands 342,344 are wrapped around the tie-down bars 393 in the housing cavity 388,while the needles 380 are stored within slots 396.

Sutures anchors according to the present invention can be used forarthroscopic procedures. The anchors are also advantageous for open andmini-open surgical procedures. Specific examples of applicableprocedures include cortical bone-soft tissue fixation, Bankart and SLAPshoulder repairs.

An exemplary method of employing the suture anchors of the presentinvention is described below with reference to FIGS. 33-36. FIG. 33illustrates a schematic cross-sectional view of bone segment 900 whichundergoes suture anchor installation according to the present invention.A punch 910 (FIG. 33) either alone or in combination with tap 500 (FIG.34) may be employed for forming a hole in bone 900 into which sutureanchor 100 is to be inserted. If bone 900 is soft bone, punch 910 may besufficient for drilling the hole. If, however, the bone is hard corticalbone, the punch/tap combination may be desirable. Preferably, thediameter of the hole formed is slightly (e.g. 1 mm) smaller than thediameter of the suture anchor to be installed, to ensure good purchaseof the suture anchor threads in the bone. Alternatively, aself-drilling/self-tapping suture anchor can be formed and inserteddirectly into bone by engaging the anchor with a driver and turning theanchor to advance the anchor directly into bone without previousformation of a hole.

FIGS. 31 and 32 illustrate an embodiment of tap 500 employed to preparea bone socket or pilot hole prior to insertion of the anchor. As shownin FIGS. 31 and 32, tap 500 includes a shaft 502 having a handle 504 ona proximal end and a tapping head 506 on a distal end. Tapping head 506includes a trocar tip 508 followed by a tapered, spiral cutting section505. Using tap 500, a hole for the suture anchor is formed toaccommodate a head of a cannulated driver used to install the sutureanchor.

Reference is now made to FIGS. 35 and 36. Driver 200 loaded with thefully-threaded suture anchor of the present invention (shown in FIG. 26,for example) is then placed at the opening of the prepared hole in bone900, and the driver 200 is rotated until the proximal surface of theanchor 100 is flush with the surface of the bone. The driver tip is thenpulled back, to reveal the suture strands 42, 44 (FIG. 36). Since it isnot necessary for the proximal end of the anchor to be countersunk belowthe bone surface to prevent tissue abrasion, the inventive anchor doesnot need to be inserted as far as prior art devices, and avoids abrasionof the sutures by the rim of the bone around the installed sutureanchor.

The suture anchor of the present invention provides advantages inaddition to those already discussed above. For example, with the threadsprovided along the entire length of the suture anchor body, the anchoris afforded maximum securement by the threads in the cortical bone,unlike some prior art anchors in which the threads only contact thecancellous bone. Also, by providing a knot which is optionally coatedwith a glue material, the suture anchor is installed with a highertorque than many prior art anchors, and thus has improved fixationstrength.

Although the present invention has been described in relation toparticular embodiments thereof, many other variations and modificationsand other uses will become apparent to those skilled in the art.

What is claimed is:
 1. A suture anchor comprising: an anchor body havinga longitudinal axis, a proximal end, and a distal end, wherein theanchor body includes a coaxial central bore located at the proximal endand a coaxial central passage extending between the central bore and thedistal end, wherein the central bore has a first dimension substantiallyperpendicular to the longitudinal axis, and the central passage has asecond dimension substantially perpendicular to the longitudinal axis,that is less than the first dimension; and a flexible strand thatextends through the central passage of the anchor body, wherein a firstknot formed in the flexible strand at the distal end of the anchor bodyhas a third dimension greater than the second dimension to prevent thefirst knot from passing through the central passage; wherein a closedloop positionable at least partially within the central bore of theanchor body is configured to be formed entirely by the flexible strand;and wherein the first knot is located within a second central bore ofthe anchor body that has a fourth dimension substantially perpendicularto the longitudinal axis that is substantially the same as the firstdimension.
 2. The suture anchor of claim 1, wherein the closed loop ispositionable completely within the anchor body.
 3. The suture anchor ofclaim 1, wherein the closed loop is located within the central bore ofthe anchor body.
 4. The suture anchor of claim 3, wherein the centralbore has an opening configured to receive a driver head for driving thesuture anchor.
 5. The suture anchor of claim 1, further comprising atleast one suture strand threaded through the closed loop.
 6. The sutureanchor of claim 5, wherein the suture strand further includes a needleattached at one end.
 7. The suture anchor of claim 1, wherein the anchorbody is threaded from the proximal end to the distal end.
 8. The sutureanchor of claim 1, wherein the anchor body comprises bioabsorbablematerial.
 9. The suture anchor of claim 1, wherein the flexible strandcomprises a suture formed of ultrahigh molecular weight polyethylene.10. The suture anchor of claim 1, wherein the first knot is coated witha glue material.
 11. The suture anchor of claim 1, wherein a distalsurface of the central bore is substantially perpendicular to thelongitudinal axis of the suture anchor.
 12. The suture anchor of claim1, wherein the anchor body only defines three different bores.
 13. Thesuture anchor of claim 1, wherein the fourth dimension of the secondcentral bore is constant.
 14. The suture anchor of claim 1, wherein theanchor body only defines a single second central bore distal to thecentral passage.
 15. The suture anchor of claim 1, wherein alongitudinal axis of the second central bore is coaxial with thelongitudinal axis of the anchor body.
 16. The suture anchor of claim 1,wherein the anchor body is a single, integral, monolithic component. 17.A suture anchor assembly for attachment of tissue to bone, the sutureanchor assembly comprising: a suture anchor comprising an anchor bodyhaving a distal end, a proximal end, a longitudinal axis, an outersurface, a coaxial central bore located at the proximal end, and acoaxial central passage extending between the central bore and thedistal end, wherein the central bore has a first dimension substantiallyperpendicular to the longitudinal axis, and the central passage has asecond dimension substantially perpendicular to the longitudinal axisthat is less than the first dimension; a first flexible strand thatextends through the central passage of the anchor body, wherein a firstknot formed in the first flexible strand at the distal end of the anchorbody has a third dimension greater than the second dimension to preventthe first knot from passing through the central passage, and wherein aclosed loop positionable at least partially within the central bore ofthe anchor body is configured to be formed entirely by the firstflexible strand; and at least a second flexible strand attached to thesuture anchor and configured to pass slidingly through the firstflexible strand wherein the first knot is located within a secondcentral bore of the anchor body that has a fourth dimensionsubstantially perpendicular to the longitudinal axis that issubstantially the same as the first dimension.
 18. The suture anchorassembly of claim 17, wherein the closed loop is configured to berecessed from the proximal end of the anchor body by about one third thelength of the anchor body.
 19. The suture anchor assembly of claim 17,wherein the anchor body comprises a plurality of thread flightsextending from the outer surface of the anchor body.
 20. The sutureanchor assembly of claim 17, wherein the anchor body has an outsidediameter of about 5.5 mm.
 21. A method of attaching a suture anchorassembly to a driver, the suture anchor assembly configured toapproximate tissue to bone and comprising a suture anchor comprising: ananchor body having a distal end, a proximal end, a longitudinal axis, acoaxial central bore located at the proximal end, and a coaxial centralpassage extending between the central bore and the distal end, whereinthe central bore has a first dimension substantially perpendicular tothe longitudinal axis, and the central passage has a second dimensionsubstantially perpendicular to the longitudinal axis that is less thanthe first dimension; a first flexible strand that extends through thecentral passage of the anchor body, wherein a first knot formed in thefirst flexible strand at the distal end of the anchor body has a thirddimension greater than the second dimension to prevent the first knotfrom passing through the central passage, and wherein a closed looppositionable at least partially within the central bore of the anchorbody is configured to be formed entirely by the first flexible strand;and at least a second flexible strand attached to the suture anchor andconfigured to pass slidingly through the first flexible strand; whereinthe first knot is located within a second central bore of the anchorbody that has a fourth dimension substantially perpendicular to thelongitudinal axis that is substantially the same as the first dimension;the method comprising the steps of: coupling the suture anchor assemblyto the driver; and threading ends of the second flexible strand througha cannula of the driver.
 22. The method of claim 21, wherein the secondflexible strand further comprises a needle attached to one end.
 23. Themethod of claim 22, further comprising the step of securing the needlewithin a cavity of a handle of the driver.